Tropical Update – September 19, 2019

Tropical Weather Outlook

NWS National Hurricane Center Miami FL

800 AM EDT Thu Sep 19 2019

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Hurricane

Humberto, located several hundred miles northeast of Bermuda,

and on Tropical Storm Jerry, located several hundred miles east of

the Leeward Islands.

1. A tropical wave located about 1000 miles west of the Cabo Verde

Islands is producing disorganized cloudiness and showers. Some

development of this system is possible while the system approaches

the Windward Islands this weekend or when it moves across the

eastern Caribbean Sea early next week.

* Formation chance through 48 hours…low…near 0 percent.

* Formation chance through 5 days…low…30 percent.

2. An elongated area of low pressure associated with a tropical wave

is located just south of the Dominican Republic. Although

upper-level winds are not conducive for significant development,

thunderstorm activity has become more concentrated since yesterday.

Some slight development is still possible before the system begins

to interact with the high terrain of Hispaniola. Regardless of

development, locally heavy rainfall is possible over portions of the

Dominican Republic and Haiti during the next day or two. The

disturbance is forecast to move slowly northwestward through the

weekend.

* Formation chance through 48 hours…low…10 percent.

* Formation chance through 5 days…low…10 percent.

3. A tropical wave is forecast to move off the west coast of Africa in

a few days. Environmental conditions are expected to be conducive

for at least gradual development thereafter while the system moves

westward over the far eastern tropical Atlantic.

* Formation chance through 48 hours…low…near 0 percent.

* Formation chance through 5 days…low…20 percent.

 

Tropical Storm Jerry – September 18, 2019

TS Jerry has formed in the Atlantic and looks like based on the official forecast that most land masses will be missed. At the end of five days the NHC forecast has TS Jerry turning and may not pose a threat to the US Coast. Still a long way out, so keep watching.

Tropical Storm Jerry Discussion Number   5

NWS National Hurricane Center Miami FL       AL102019

1100 AM AST Wed Sep 18 2019

Satellite images indicate that Jerry continues to become better

organized, with a large curved band wrapping around the center.

While microwave data does not show an inner core yet, the overall

satellite presentation has improved during the past several hours.

The initial wind speed is set to 45 kt, which closely matches

almost all of the available Dvorak estimates and a just-arrived

ASCAT-C scatterometer pass.

Further intensification of Jerry is expected during the next day or

two as the cyclone moves over very warm waters within light shear.

While this type of environment could support even more

strengthening than forecast, there is some substantial dry air

around the cyclone, which is forecast to limit the intensification

rates for now.  This forecast leans heavier on the regional

hurricane models HWRF, HMON and COAMPS-TC, which all show a weaker

cyclone than the statistical/dynamical LGEM and SHIPS models.

Most of the guidance shows increasing shear in a couple of days, and

the shear could become somewhat strong by next week.  While little

change in strength is indicated beyond Friday, this usually doesn’t

happen in reality, and further changes will be necessary as the

environmental factors become more clear.

The initial motion continues to be west-northwestward, or 290/12

kt.  The subtropical ridge to the north should steer Jerry at a

faster forward speed for the next couple of days.  Afterward, a

northwest to north-northwestward turn, influenced by a weakness in

the aforementioned ridge left behind by Humberto, is expected. The

NHC track forecast is basically an update from the previous advisory

and lies on the left side of the guidance suite, nearest the ECMWF

model and the corrected-consensus forecasts.

Key Messages:

1. Jerry is expected to strengthen and be a hurricane when it moves

near the northern Leeward Islands Friday, although it is too soon to

determine the direct impacts to the islands. Interests there should

ensure they have their hurricane plan in place and monitor the

progress of this system.  Watches could be issued for a portion of

this area this afternoon or evening.

FORECAST POSITIONS AND MAX WINDS

INIT  18/1500Z 14.6N  49.2W   45 KT  50 MPH

12H  19/0000Z 15.3N  51.0W   55 KT  65 MPH

24H  19/1200Z 16.3N  53.7W   60 KT  70 MPH

36H  20/0000Z 17.3N  56.5W   65 KT  75 MPH

48H  20/1200Z 18.4N  59.5W   65 KT  75 MPH

72H  21/1200Z 20.5N  65.3W   65 KT  75 MPH

96H  22/1200Z 23.3N  69.1W   65 KT  75 MPH

120H  23/1200Z 26.5N  70.5W   60 KT  70 MPH

 

Tropical Depression #10 – September 17, 2019

Weekly_Outlook (2)

 

Tropical Depression Ten Discussion Number   1

NWS National Hurricane Center Miami FL       AL102019

1100 AM AST Tue Sep 17 2019

Deep convection associated with the area of low pressure over the

central Atlantic has become more persistent and better organized

this morning.  Data T-numbers from both SAB and TAFB are 2.0 on the

Dvorak scale, therefore advisories are being initiated on a tropical

depression.  The initial intensity is set at 30 kt, in line with the

satellite estimates.  The depression is forecast to move over

gradually increasing sea surface temperatures within a favorable

upper-level environment.  The only negative factor for

intensification appears to be some nearby dry air, but with low

shear conditions expected, so steady strengthening is forecast

during the next several days.  The NHC forecast calls for the

depression to become a tropical storm later today, and attain

hurricane status within 72 hours. The NHC intensity forecast is in

good agreement with the SHIPS and LGEM statistical models.

Since the depression is still in the development phase, the initial

motion is a somewhat uncertain 295/10 kt.  A strong deep-layer

ridge to the north of the cyclone should steer the depression

generally west-northwestward at a faster forward speed during the

next few days.  The track guidance is in relatively good agreement

through 72 hours, and brings the cyclone near the northern Leeward

Islands in about 3 days.  By late in the period, the cyclone is

expected to reach the western periphery of the ridge, and there is

increasing spread among the guidance.  The global model ensemble

means are along the right side of the envelope while the HWRF and

UKMET are along the left side.  The NHC track lies close the

consensus aids, which is also in good agreement with the latest

ECMWF.

Interests in the northern Leeward Islands should monitor the

progress of this system.

FORECAST POSITIONS AND MAX WINDS

INIT  17/1500Z 12.9N 44.9W  30 KT  35 MPH

12H  18/0000Z 13.8N 46.1W  35 KT  40 MPH

24H  18/1200Z 14.7N 47.9W  40 KT  45 MPH

36H  19/0000Z 15.5N 50.2W  45 KT  50 MPH

48H  19/1200Z 16.3N 52.9W  55 KT  65 MPH

72H  20/1200Z 18.2N 59.2W  65 KT  75 MPH

96H  21/1200Z 20.2N 64.7W  75 KT  85 MPH

120H  22/1200Z 22.5N 69.0W  80 KT  90 MPH

Tropical Weather Update – September 13, 2019

Potential Tropical Cyclone Nine Discussion Number   4

NWS National Hurricane Center Miami FL       AL092019

1100 AM EDT Fri Sep 13 2019

Preliminary data from a reconnaissance plane indicate that the

disturbance has not developed a well-defined center yet and

continues to be characterized by an elongated SW to NE trough of low

pressure.  Satellite images however, suggest that the system could

be consolidating a little bit farther to the east within the area of

deep convection.  The reconnaissance plane will also check this

region soon.  In this advisory, the initial position is a point near

the middle of of the trough, but not quite as far east as the

convective area. The initial intensity remains 25 kt.

The disturbance is embedded within a moderate shear environment, but

this parameter is not expected to be strong enough to halt

development. The NHC forecast still calls for this system to

become a tropical cyclone later today or Saturday. Global models

develop the system and guidance suggests that the cyclone could even

reach hurricane intensity by the end of the forecast period. By

then, the system is expected to be over the Atlantic well southeast

of the coast of the Carolinas.

Due to a lack of a well-defined center, the initial motion is highly

uncertain. It appears that there has been little motion during

the past few hours. A weakness in the ridge over the western

Atlantic is forecast to develop and this pattern should steer the

system slowly toward the northwest and then northward. In about 3

days, an eastward moving mid-latitude trough will force the system

to recurve away from the coast toward the Atlantic.  The guidance

has shifted a little to east this morning and consequently the NHC

track forecast was adjusted in that direction. However, the official

forecast is still on the western edge of the guidance envelope. If

the disturbance develops a little more to the east, the track

forecast will probably adjusted to the right later tod

 

 

Tropical Weather Update – September 12, 2019

To All,

A couple of systems we need to keep a eye on a possibility they could be a problem next week.

Tropical Weather Outlook

NWS National Hurricane Center Miami FL

800 AM EDT Thu Sep 12 2019

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

1. Satellite images indicate that the area of disturbed weather over

the central and southeastern Bahamas is gradually becoming better

organized while surface pressures are falling in the area.

Conditions are becoming favorable for a tropical depression or a

tropical storm to form within the next day or so as the system moves

toward the northwest through the northwestern Bahamas and toward

the Florida Peninsula at 5 to 10 mph. If this development trend

continues Potential Tropical Cyclone advisories will likely be

initiated later today. This disturbance will bring heavy rainfall

and gusty winds across portions of the Bahamas through Friday,

especially in portions of the northwestern Bahamas affected by

Hurricane Dorian. An Air Force Reserve reconnaissance aircraft is

scheduled to investigate the system this afternoon, if necessary.

* Formation chance through 48 hours…high…70 percent.

* Formation chance through 5 days…high…80 percent.

2. A tropical wave located several hundred miles west of the Cabo

Verde Islands is producing disorganized showers and thunderstorms.

Conditions appear conducive for development, and a tropical

depression could form early next week while the system moves

westward over the tropical Atlantic.

* Formation chance through 48 hours…low…near 0 percent.

* Formation chance through 5 days…medium…40 percent.

Tropical Weather Outlook – September 9, 2019

Tropical Weather Outlook

NWS National Hurricane Center Miami FL

800 AM EDT Mon Sep 9 2019

For the North Atlantic…Caribbean Sea and the Gulf of Mexico:

The National Hurricane Center is issuing advisories on Tropical

Storm Gabrielle, located over the north-central Atlantic Ocean.

1. A weak area of low pressure, associated with a tropical wave,

continues to produce disorganized showers and thunderstorms

about midway between the Cabo Verde Islands and the Windward

Islands. Some slow development of this system is possible during the

next two or three days before upper-level winds become unfavorable

for tropical cyclone formation. This system is expected to move

generally westward across the tropical Atlantic Ocean for the next

several days.

* Formation chance through 48 hours…low…20 percent.

* Formation chance through 5 days…low…30 percent.

2. Disorganized cloudiness and showers located a few hundred miles

north and northeast of the Greater Antilles are associated with a

surface trough interacting with an upper-level low. Little to no

development of this system is expected during the next day or two

while the system moves west-northwestward, north of the Greater

Antilles. Environmental conditions could become a little more

conducive for development when the disturbance moves near the

Bahamas and Florida late this week.

* Formation chance through 48 hours…low…near 0 percent.

* Formation chance through 5 days…low…20 percent.

Translate »